Floor underlayment



FIG. 1 is a perspective view of my new floor underlayment;

FIG. 2 is a side elevational view of my new floor underlayment of FIG. 1, the other sides being mirror images thereof;

FIG. 3 is top plan view of my new floor underlayment of FIG. 1;

FIG. 4 is a bottom plan view of my new floor underlayment, opposite that of FIG. 3; and,

FIG. 5 is a bottom perspective view of my new floor underlayment, opposite that of FIG. 1. 

CLAIM The ornamental design for a floor underlayment, as shown and described. 